A prominent speaker at a “Stop the Steal” rally held by Trump supporters in Washington the day before the storming of the Capitol was taken into custody Monday on charges of impeding police during the riot.

Brandon Straka, 44, of New York was arrested in Nebraska on a felony charge of interfering with police during civil disorder, and illegal entry and disorderly conduct on restricted Capitol grounds.

The arrest came as federal prosecutors in court filings condemned what they called the Jan. 6 insurrection at the U.S. Capitol, which delayed the certification of Joe Biden’s electoral victory, led to the deaths of four rioters and one police officer, and resulted in assaults on about 139 Capitol and D.C. police officers.

“Every person who was present without authority in the Capitol on January 6 contributed to the chaos of that day and the danger posed to law enforcement, the Vice President, Members of Congress, and the peaceful transfer of power,” U.S. counterterrorism and public-corruption prosecutors wrote Sunday in documents for one arrestee who had been photographed with zip ties in his hand during the riot.

They added, “Make no mistake . . . the imprint on this country’s history of a militia clad insurrectionist standing over an occupied Senate chamber is indelible.”

Straka, a former New York City hairstylist and self-described former liberal, amassed more than 550,000 Twitter followers and became a Fox News contributor after posting a viral video in May 2018 describing why he left the Democratic Party.

The founder of the WalkAway Campaign, Straka has since said on social media that he saw “nobody committing any acts of violence” or vandalism on Jan. 6 and that Trump supporters were able to file into the Capitol.

Supporters of President Trump crossed barricades and began marching toward the back of the U.S. Capitol on Jan. 6. (The Washington Post)

However, an arrest warrant and affidavit filed Jan. 20 and made public Tuesday cited a witness and Facebook posts allegedly showing otherwise.

In one, the FBI affidavit said, Straka recorded himself in front of a mobbed entrance to the Capitol, urging a crowd to wrest away a riot shield from a police officer and shouting: “Take it away from him. . . . Take the shield! . . . Take it! Take it!”

At another point, Straka stood behind a crowd of people trying to push their way in, yelling, “Go! Go!” and saying, “I wanna try,” the FBI said.

Charging papers say Straka was wearing the same coat as in a recording taken the previous day when he was introduced and spoke for about five minutes at a Jan. 5 rally of Trump backers at Freedom Plaza in Washington, at which he addressed attendees “as ‘Patriots’ and referenced the ‘revolution’ multiple times.”

“Straka told the attendees to ‘fight back’ and ended by saying, ‘We are sending a message to the Democrats, we are not going away, you’ve got a problem!’ ” the FBI said.

Information about an attorney for Straka was not immediately available.

Straka’s case was docketed as previously charged defendants continued to make initial appearances and face detention hearings across the country.

In D.C., prosecutors said a Pennsylvania woman who was accused by a former romantic partner of stealing a laptop from House Speaker Nancy Pelosi’s office has destroyed evidence and encouraged others to do the same.

Riley June Williams, 22, was released to home confinement with her mother in Harrisburg, Pa., however, after prosecutors did not request her further detention.

In a court hearing, Justice Department senior trial attorney Mona Sedky said, “We were already aware . . . that [Williams] was deleting her own online accounts and possibly switching devices.” The prosecutor added, “What we had learned recently is that we also think she might be instructing other people to delete messages as well.”

A public defender said he needed more time to review those allegations.

U.S. Magistrate Judge Zia M. Faruqui expressed surprise that prosecutors agreed to Williams’s release, calling the allegations against her “extremely troubling.”

The prosecutor asked that Williams be ordered to stay away from computers and the Internet and to undergo a mental health screening, out of “personal interest in the defendant’s safety and well-being.” A hearing for Williams is scheduled to resume Tuesday.

Williams surrendered to authorities on Jan. 18, a day after she was charged with unlawful entry and disorderly conduct on Capitol grounds. An FBI affidavit alleged that she appeared to have filmed and shared a video of another person lifting an HP computer off a desk inside the Capitol.

The affidavit links to images of all-caps, typo-riddled social media posts from a user named “Riley” who declares that they “STOLE . . . FROM NANCY POLESI.”

“I TOOK HER GRAVEL HAMMWR TBING,” one post reads, according to the affidavit.

“I DOMT CARE I TOOK NANCY POLESIS HARD DRIVES I DON’T CARE KILL ME,” reads another message the affidavit cited.

A former boyfriend told federal agents that Williams planned to sell the laptop to a friend who could pass it to Russian intelligence, according to prosecutors, but that the sale did not take place. Through a public defender, she has said that the ex-boyfriend was abusive and that she changed her number to avoid him, not the authorities.

U.S. Capitol Police confirmed that an HP laptop was stolen from the speaker’s office, the FBI said. Drew Hammill, deputy chief of staff for Pelosi, said Jan. 8 that a laptop “only used for presentations” had been taken from a conference room.

Williams was charged with aiding or abetting the theft of government property, but the FBI did not allege that she personally took the device, adding that its whereabouts were unknown.

In Maryland, Matthew Ryan Miller was taken into custody and charged with using and carrying a deadly weapon in the riot; he allegedly discharged a fire extinguisher at police guarding a packed Capitol entrance.

The FBI cited witness and photo identifications of a man they say is Miller, wearing a black cowboy hat, goggle-style sunglasses and a Washington Capitals jersey, and at times carrying a Maryland state flag and the Gadsden flag, known for its “Don’t Tread on Me” motto.

At a hearing Monday, a defense attorney argued that there was “no indication he used the fire extinguisher as a weapon,” only that he “allegedly discharged it,” and that the identification of Miller in a Getty Images photo might have been inaccurate.

Assistant U.S. Attorney Kaitlin Ann Vaillancourt said the government intends to seek an indictment for assault on a law enforcement officer, among other felonies. A judge ordered Miller detained, saying his action endangered officers trying to protect the Capitol.

Correction: This story has been updated to reflect that it was prosecutors’ request, not a judges order, to keep Williams away from computers and the Internet at Monday’s hearing.